Tim Evans' site on Complex Networks

Author: T.S.Evans (Page 3 of 4)

Geographies of the world’s knowledge

This report came to my attention a short while ago, it was sent to me by a colleague at the University of Oxford.  While most of this blog is about social media, science, networks and ranking, which we might think of as the “weather” in science this report it more of a “climate” analysis.  Anyone who is interested understanding the trends of science on a century by century timescale would do well to read this report.  Although it is very much an executive summary, there is some good commentary and the report contains some carefully considered and beautifully produced infographics.

The report is available on request from http://www.convoco.co.uk/editions.

The Connected Past: academia at its best

The Connected Past Logo

Just back from an excellent meeting which pulled together people interested in networks and complexity in archaeology and history. The Connected Past (twitter hash tag #connectedpast) was held at Southampton as a two day symposium preceding the CAA 2012 conference (Computer Applications and Quantitative Methods in Archaeology). There was an incredible range of speakers and as they were all recorded you should be able to find the talks on line eventually.

At one end Astrid Van Oyen from Cambridge talked about Actor Network Theory which seemed to me to be a good example of what researchers in social sciences understand to be a theory. That is it seemed to be largely about concepts and described in terms of words, certainly no equations, so nothing like the theories I am used to. However my experience over the last decade has been that physical scientists should not be too quick to dismiss these types of theory. The thoughts and ideas in social science theories can be used to mould the numerical models and theoretical equations which I associate with a theory.

My work on archaeological models lies at the other extreme, and we had many examples at this end too. The work of a University of Sheffield group, as described by Caitlin Buck, was a good example here. This uses Bayesian methods to produce models for the spread of agriculture across Europe but ones which are firmly based on the data (including its uncertainty), in this case carbon dated finds of cultivated cereal grains. It takes five days of computer time to produce a spatial temporal map of the spread of agriculture across Europe so it is a real challenge for the physical scientists.

I can’t resist mentioning my colleague, Ray Rivers too.  I am not sure if archaeologists like his  description of Knossos as being (in some models) the “Tescos of the Aegean” (you can replace Tescos with WalMart or any other appropriate supermarket chain)  if they found the idea that Margaret Thatcher went wrong because she placed had too much trust in Agent Based Modelling helpful.  However underneath his flowery turn of phrase was a serious message echoed by several others, that is trying to understand what we can learn from models.

Overall one of the most enjoyable meetings I have been too. The range of topics and knowledge meant there was lots of for me to take away and I hope I gave something new to others too. There is a new wave of archaeologists who can see the utility of these new ideas and tools and as a complement to existing methods. This field is part of the Digital Humanities movement as information technology delivers new avenues of research for the social sciences. The popularity of the meeting showed that in archaeology this approach has now reached a critical mass.

Perhaps the main question I came away with is “what are we delivering with these new tools”? This was one of the themes suggested by Carl Knappett from Toronto (literally as he gave his talk over Skype – a first for me at a conference). Carl suggested it was time for the field to mature and I agree with that. For this we need physical scientists to work with data and for archaeologists to become confident in working these new tools.

The Connected Past keynote speaker Carl Knappett

The Connected Past keynote speaker Carl Knappett

The overriding feeling though is one of excitement, new ideas, new opportunities, along with the challenge of what are we going to deliver. The organisers, Tom Brughmans (University of Southampton), Anna Collar (University of Liverpool) and Fiona Coward (Royal Holloway University of London) are to be praised for doing such a good job with such a timely meeting. The Connected Past meeting was academia at its best.

The Organisers of the Connected Past Meeting, Southampton 2012

The Organisers of the Connected Past Meeting, Southampton 2012

Citeology

Well, we all know that adding “-ology” to a word makes it a science – geology, biology, scientology – oh, well, perhaps not scientology.  The citeology project at Autodesk Research is a wonderful visualisation that shows the temporal relationship between references.  The corpus to which the analysis is applied is currently quite small, extending to some 3502 papers in Human Computer Interaction conferences between 1982 and 2010 – 11699 citations are tracked.  The ensuing diagrams give a compelling visualisation showing quickly just how many citations have been made to articles and in the corpus, which articles are uncited and what the temporal “reach”  of an article has been.  There is a nice app on the page that allows you to explore the data set.  While this works well for smaller datasets, I wonder how this approach could be scaled to work with something of the size of the Web of Science or Scopus data sets?

Evidently, Justin Matejka is the force behind this work – a contact link can be found to him on the page mentioned above.  A paper describing the approach by Justin and his colleagues Tovi Grossman and George Fitzmaurice is available here http://autodeskresearch.com/publications/citeology2.

A lifetime in numbers

While this article isn’t particularly about network theory it is an excellent study in what can be done with some data, a computer and a small amount of time.  Wolfram explores the numbers (and distributions) behind his email…  An amusing analysis: http://blog.stephenwolfram.com/2012/03/the-personal-analytics-of-my-life/.  Candidly, the aim of the article is to show off the new Wolfram Alpha Pro offering.  The graphs are cute and the comemntary is fun.  But, given the nature of the data and the power of the computational tools available to Dr Wolfram, why not a network analysis?

Who’s #1?: The Science of Rating and Ranking

I’ve recently been reading Langville and Meyer’s book, Who’s #1?: The Science of Rating and Ranking.  This is a neat book filled with nice ideas, which are clearly explained.  This isn’t Langville and Meyer’s first foray into helping popularise ranking, having previously written: Google’s PageRank and Beyond: The Science of Search Engine Rankings.  While that book concentrated more specifically on the ideas behind Google’s PageRank algorithm, the current offering covers a slightly wider range of material.  However, as with the first book, the material is interesting, and well explained.  I think that it would be useful for anyone wanting to teach a course on ranking, and covers some excellent areas that could be used for special topics lectures or guest lectures.  The material is well presented and would make good reading for undergraduates and some advanced high school students.  Having had fun with football ranking problems a few years ago, I found this book to be nice summary of the area.  Great read!

http://press.princeton.edu/titles/9661.html

University Rankings Symposium

Every year, university rankings get a lot of coverage at particular times.  I recently noticed this set of conferences held by the Public Policy Exchange in Belgium.  I’m not sure if this will fuel the trend of ranking or whether there will be a more sober or subtle view.  Of course, we can always hope of the latter.  If you’re interested in following the event then the details are here: http://publicpolicyexchange.co.uk/events/CD12-PPE2.php

Elsevier’s Bibliometric Research Program

Here’s an interesting one… Elsevier are drawing attention to their bibliometric research program – this is a way for researchers to bid (in the same way that we bid for research grants) for free access to particular parts of the Scopus / Sciverse / ScienceDirect databases for the purposes of research.  It seems that this move would be excellent for bibliometric researchers and should lead to a better understanding of the quality and evenness of these data sources.  The panel to evaluate proposals includes a pretty impressive list of experts – so, better get those thinking hats on!  One question – do I have to publish the research in an Elsevier journal?

Find out more: http://ebrp.elsevier.com/index.asp

User Activity on Google+

I saw this excellent video visualizing the growth of Google plus usage on Visua.ly this morning and I thought that I would share it.  This is a really nice “real time” visualization that shows some good usage of clustering and visualisation tools.  The explanations behind the dataset used together with the full video can be found on visua.ly: http://visual.ly/user-activity-google.

Boolean decision problems with competing interactions on scale-free networks: Critical thermodynamics

New posting to arXiv: this paper considered the thermodynamics of Boolean variables on scale-free networks – with the fascinating result that there is a phase transition if the graph is scale-free.

The abstract is:

We study the critical behavior of Boolean variables on scale-free networks with competing interactions (Ising spin glasses). Our analytical results for the disorder/network-decay-exponent phase diagram are verified using large-scale Monte Carlo simulations. When the probability of positive (ferromagnetic) and negative (antiferromagnetic) interactions is the same, the system undergoes a finite-temperature spin-glass transition if the exponent that describes the decay of the interaction degree in the scale-free graph is strictly larger than 3. However, when the exponent is equal to or less than 3, a spin-glass phase is stable for all temperatures. The robustness of both the ferromagnetic and spin-glass phases suggest that Boolean decision problems on scale-free networks are quite stable to local perturbations.

The paper can be downloaded from arXiv at: http://arxiv.org/abs/1202.1153

 

Beyond conventional publication metrics?

I’ve recently been looking around to work out how to tell what impact my research has.  Altmetric and Total-Impact think that they have the answer.  Both services aim to quantify the extend to which piece of scholarly work has been “noticed” in the blogosphere.

Altmetric looks to be a little more of a commercial offering and has a similar feel to musicmetric that we mentioned in an earlier post.   Created by Euan Adie of Digital Science to contextualise research work, Adie won Elsevier’s competition for using the SciVerse API while putting Altmetric together.

Total Impact is the result of a brainstorming session at Cameron Neylon‘s Beyond the Impact workshop in London last year.  One of the leading lights behind the development, Jason Priem, made the news recently explaining the reason for the project.

Both data sets are growing with time and are likely to hook into more sources.  Both have data APIs:

Surely…a challenge to play with data as rich and complex as this!

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