your two questions

Tue Mar 6 02:20:34 EST 2007

Dear David, 

My first question is, does every initial transaction between two people, no
matter how slight, establish a link in the network? The alternative might be
that certain thresholds of interaction must apply, such as co-authorship or
citation. My second question is, do you think that the strength of a link
might usefully be measured by the amount of information that passes between
the people linked?

1. As may be clear from my previous answer, I would consider a
zero-transaction also as a link, but with the value of zero. The network is
to be defined as the system of reference. For example, if one studies the
network of international coauthorships, there may be no transactions between
two countries in a certain year. The matrix would then have a value of zero
in this cell. The expectation based on the margintotals for these two
countries may be different from zero. 

2. Yes. For example, in the network of international coauthorships the
number of publications is usually counted. One can try to refine this by for
example counting the number of coauthored words. The strength of the links,
however, is also dependent on the meaningfulness of the information and that
would lead me back to the previous communication. Inter-human communication
is more complex than the communication between computers. Perhaps, the
strength of the links between two servers can meaningfully be
operationalized as the amount of information that passes between them.

With best wishes, 

Loet
  _____  

Loet Leydesdorff 
Amsterdam School of Communications Research (ASCoR)
Kloveniersburgwal 48, 1012 CX Amsterdam
Tel.: +31-20- 525 6598; fax: +31-20- 525 3681 
 <mailto:loet at leydesdorff.net> loet at leydesdorff.net ;
<http://www.leydesdorff.net/> http://www.leydesdorff.net/ 

Now available:
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The Knowledge-Based Economy: Modeled, Measured, Simulated. 385 pp.; US$
18.95 
 <http://www.universal-publishers.com/book.php?method=ISBN&book=1581126956>
The Self-Organization of the Knowledge-Based Society;
<http://www.universal-publishers.com/book.php?method=ISBN&book=1581126816>
The Challenge of Scientometrics

  _____  

From: ASIS&T Special Interest Group on Metrics
[mailto:SIGMETRICS at LISTSERV.UTK.EDU] On Behalf Of David E. Wojick
Sent: Monday, March 05, 2007 8:32 PM
To: SIGMETRICS at LISTSERV.UTK.EDU
Subject: Re: [SIGMETRICS] preprint version "Globalisation in science in
2005"

I am afraid I understand very little of what you have written. Not enough to
grasp the answers to my two questions. You (seem to) say that transmission
(via transactions) supplies variation to the network but I would think it
was the primary process that constitutes the network. You say that the
structure of the network is selective and I do not understand what that
means. Do you mean that the structure takes the form it does because the
people are selective in whom they communicate with? In that case I agree
but, again, it makes transactions the basic unit.

Retention I do not understand, nor much of the rest. Meaning, degree of
freedom, stabilization, etc. I use all these words but not in your way
apparently. You are using a technical language that I do not speak. Is this
the language of network science?  Is there something I can read to learn it?

All my best,

David

At 02:36 AM 3/5/2007, you wrote:

Dear David, 

Indeed, there is always a substantive side to the information transmission:
something is communicated. However, from the perspective of the network this
mainly provides the variation. The network is spanned by these bottom-up
processes, but then it is also a structure (it contains an architecture).
The structure is selective. Because the network is changing, the selection
mechanism is also at variance over time. Some selection can then be selected
for stabilization. This provides the retention mechanism. 

So far, the metaphor is biological. However, in social networks one can
expect one more degree of freedom because we also give meaning to the
information exchange and the meaning exchanges feedback on the information
exchanges. Therefore, some stabilizations can also be selected for
globalization. Thus, one obtains a non-linear dynamics of communication.
However, each communication also remains an "information transaction:" it is
not either ... or, but both. Or even better: all four dimensions of
probabilistic entropy.

The information transaction alone is just a vector. The network can be
represented as a matrix. A network at each moment of time can be modeled as
a cube of information. For example, a trajectory can be shaped within this
cube. A trajectory which can be changed by (inter-)human intervention
provides us with a hypercube of information (in four dimensions).

With best wishes, 

Loet

  _____  

Loet Leydesdorff 
Amsterdam School of Communications Research (ASCoR)
Kloveniersburgwal 48, 1012 CX Amsterdam
Tel.: +31-20- 525 6598; fax: +31-20- 525 3681 
loet at leydesdorff.net  <mailto:loet at leydesdorff.net> ;
http://www.leydesdorff.net/ 

Now available:
<http://www.universal-publishers.com/book.php?method=ISBN&book=1581129378>
The Knowledge-Based Economy: Modeled, Measured, Simulated . 385 pp.; US$
18.95 
The
<http://www.universal-publishers.com/book.php?method=ISBN&book=1581126956>
Self-Organization of the Knowledge-Based Society; The
<http://www.universal-publishers.com/book.php?method=ISBN&book=1581126816>
Challenge of Scientometrics

  _____  

From: ASIS&T Special Interest Group on Metrics [
<mailto:SIGMETRICS at LISTSERV.UTK.EDU> mailto:SIGMETRICS at LISTSERV.UTK.EDU] On
Behalf Of David E. Wojick

Sent: Sunday, March 04, 2007 8:01 PM

To: SIGMETRICS at LISTSERV.UTK.EDU

Subject: Re: [SIGMETRICS] preprint version "Globalisation in science in
2005"

This study is very interesting in the context of my
http://www.osti.gov/science.world/ project. But on a tangential note, your
mention of strong and weak links brings up a basic question about network
analysis, about which I know little. 

I have a conceptual model of science diffusion in which the basic element is
the "information transaction." This is basically one person getting
information from another. My reading your paper for example. Note that
transactions have quantity as well, such as reading your email, your
abstract, part of your paper, all of it, etc.

My first question is, does every initial transaction between two people, no
matter how slight, establish a link in the network? The alternative might be
that certain thresholds of interaction must apply, such as co-authorship or
citation. My second question is, do you think that the strength of a link
might usefully be measured by the amount of information that passes between
the people linked?

If these issues are already discussed in the literature I shall be happy to
look at it. It is important because the vast majority of transactions cannot
be observed, just as in other cases of diffusion.

Best regards,

David

At 04:11 AM 2/27/2007, you wrote:

Globalisation in  <http://www.leydesdorff.net/cswagner07/index.htm> the
network of science in 2005:

The diffusion of  <http://www.leydesdorff.net/cswagner07/index.htm>
international collaboration and the formation of a core group

 <http://www.leydesdorff.net/cswagner07/Globalisation.pdf> []
<http://www.leydesdorff.net/cswagner07/Globalisation.pdf> <click here for
pdf>

Caroline S. Wagner

SRI International, Arlington, Virginia, 22209, USA

Caroline.wagner at sri.com; http://www.cswagner.net <http://www.cswagner.net/> 

Loet Leydesdorff

University of Amsterdam, Amsterdam School of Communications Research (ASCoR)

Kloveniersburgwel 48, 1012 CX Amsterdam, The Netherlands

International collaboration as measured by co-authorships on refereed papers
grew significantly from 1990 to 2005. International communications in
science can best be studied as a network, since there is no political
institution mediating relationships at that level: links self-organize
largely through contacts made by scientists. As such, science at the
international level shares features with other complex adaptive systems
whose order arises from the interactions of hundreds of agents pursuing
self-interested strategies. Communications at the international level
appears to have grown significantly in the 1990s, with the addresses of many
more countries evident in collaborative articles. By 2005, global
communications appear to have reinforced the formation of a core group of
highly cooperative countries. This core group can be expected to use
knowledge from the global network with great efficiency, since these
countries have strong national systems. Countries at the periphery may be
disadvantaged by the strength of the core.

  _____  

Loet Leydesdorff 

Amsterdam School of Communications Research (ASCoR)

Kloveniersburgwal 48, 1012 CX Amsterdam

Tel.: +31-20- 525 6598; fax: +31-20- 525 3681 

loet at leydesdorff.net  <mailto:loet at leydesdorff.net> ;
http://www.leydesdorff.net/ 

Now available: The
<http://www.universal-publishers.com/book.php?method=ISBN&book=1581129378>
Knowledge-Based Economy: Modeled, Measured, Simulated . 385 pp.; US$ 18.95 

The
<http://www.universal-publishers.com/book.php?method=ISBN&book=1581126956>
Self-Organization of the Knowledge-Based Society; The
<http://www.universal-publishers.com/book.php?method=ISBN&book=1581126816>
Challenge of Scientometrics

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