To paraphrase Dr. Rick Sloot’s address at the ceremonial opening of University of Amsterdam’s Institute for Advanced Systems - if you put together a philosopher and a theoretical physicist together and ask them to “make something”, they may not know where to begin.
That’s where complexity science comes in.
This burgeoning research arena, wearing hand-me-downs from theoretical physics and math (probability, graph theory), has been delightfully uprooting classical theory in economics, neuroscience, and biology (amongst other disciplines) for over a decade, calling all scientists to take a deeper look into how network science might apply to their field.
The first day of the Complex Systems Society’s 2016 Conference on Complex Systems was filled with over 100 talks, so unfortunately my notes only make up a small sample size.
Here are some key take aways:
J. DOYNE FARMER The first bullet point in Farmer’s talk was “evolution of collective consciousness”, which set a nice tone for his examination of trends in complexity economics. He illustrated how economic models must make certain assumptions about the rationality of its agents, discussed DSGE (dynamic stochastic general equilibrium) models, expanded assumptions of complexity economics (e.g. agents have preferences and beliefs), flagged the need for standardized agent based modeling software, and announced his forthcoming launch of an open source library where anyone can join his team and “help build a new economy”. And finally, in regards to the temporal market oscillations he demonstrated in his data (pronounced as endogenous to the system), he offered an apt quote from Austrian economist Joseph Schumpeter, “we need these gales of creative destruction”, which I thought set the day up well by flagging the interplay of birth and death in nature’s cycles (which we should expect to see reflected in our models of natural systems).
SONIA KÉFI Hailing from CNRS’s Institute of Science and Evolution in Marseilles, Sonia wasted no time in reminding us that our choice of scale in evolutionary observations may contribute to us missing part of the story. She guided us through two key principal foundations: 1) Gause’s competitive inclusive principal, and 2) the paradox of plankton (first described in 1961 by Hutchinson). From these she explored the hypothesis that stability should increase as networks links increase, calling forth the work of Robert May as support for the interplay of stability and complexity. The rest of the talk was dedicated to sharing her research paradigm and results, an example of research on multiplex ecological networks.
MISAKO TAKAYASU This was a super fun, super dense (in terms of needing to squint to read equations) talk about B to B firm statistics and dynamics in Japan. I was moved by her presentation of how B to B connections can have dramatic, un-anticipated, effects on the system as a whole, which was particularly visible in her post-tsunami analyses of the Japanese auto industry. She also announced Japan’s RESAS society as a source of information on applications of econophysics.
ED BULLMORE While somber, this was my favorite talk of the day. The overall theme was connectomics and the tradoffs between neural topological development and energy use. I particularly liked the reminder that the brain uses 20% of our body’s energy, yet makes up only 2% of our body’s mass. This elevates the need for developmental tradeoffs, which have ramifications that affect the organism’s cognition, but could also be abstracted out to networks in other domains (e.g. economics). I can’t tell you how refreshing it was to see N=20,000 in his analysis! Big data is here! He effectively demonstrated the presence of the “rich club” of central (network) neural nodes, yet reminded us that there is still a great need in describing the cognitive value of topological integration. This is work I am excited to support, and I left the talk buzzing with research ideas.
J. STEPHEN LANSING This was a very thoughtful survey of the Subak system of rice field irrigation in Bali, shared by a leading anthropologist with a deep care for traditional Balinese customs, as well as a key leader in complexity theory (a refreshing multi-contextual perspective). It was a brief talk, but showed the presence of a stable equilibrium in the Subak system as a whole, maintained through religious ritual, yet modelable using a series of computation iterations whereby the methods of successful fields are applied in subsequent seasons to neighbors until an equilibrium is reached. Once again, as was the theme of the day, the computational model was tested against field data to pleasing effect.
JOHANNA MEIJER Talk on the suprachiasmatic nucleus (SCN), “the master clock in the mammalian brain and consists of 20,000 individually oscillating cells”. Presented data from mice that showed the interaction of cycles of oscillation during sleep, followed by an immediate tapering off upon waking. Also showed how the cells become desynchronized with age, leading to a decrease of the amplitude of the clock, making it “less strong at driving the circadian rhythm”. Of note was her nice reminder that the phase differences of individual cells “determine together the sinusoidal oscillations of the the SCN”.
CHRISTIAN BECKMANN I really enjoyed Christian’s rallying cry in his encouragement that we preserve topographical information as a key feature in our analysis. After hearing talks on neural networks that quickly move away from spatial relevance, this reminder was refreshening (as regions of the brain have developed in a spatial reality and offer rich insights into form and function). He focussed on data from retinotopic mapping of the visual system, using mate matching in the connectomic mapping of spectral embedding and estimating multiple modes from the resting rate.
REMCO HOGSTAD This mathematician aimed to answer the question, “what is a good network model for brain functionality”. In particular, he aimed to reconcile two approaches: 1) inhomogeneous random graphs (rgs), using vertex weights with scale-free behavior (not a spatial model), and 2) instantaneous percolation. In particular he tried to illustrate how the combination of the benefits of these two modes (weights and dependence on space, respectively) could be applied to analyzing the dynamic tradeoffs between learning in pruning in the brain.
ANGELO BIFONE This was an enjoyable exploration of methods, including “Surprise, a recently proposed binary fitness function based on probability theory”. Using the surprise quality function you get rid of issues of resolution limit, but there are fewer significant regions. Using asymptotized surprise supports weighted graphs. Referenced neuroSim R package, LFR models, Rician distribution, and Fisher’s transformations.
PREJAAS TEWARIE Discussed multilayer MEG networks, using a layered approach to analyzing mappings of functional and anatomical networks. In this way, function is determined as the weighted sum between all possible random walks through each node.
SERGIO ANDREOZZI Spoke of his work at EGI foundation, including the cloud capabilities of EGI’s linking of 300 data centers. He discussed policy initiatives of the EU in four sub-regions of open data: research data, instruments, digital services, and knowledge/expertise.
FERMIN SERRANO Presented an exciting open research lab project in Zaragoza, sponsored by the Fundación Ibercivis. The Etopia Center for Art & Technology is helping non-academic citizens conduct research, and their researchers are winning awards. In particular I was interested to hear the number of participants (in the thousands) they have rallied for crowdsourcing analysis and methods validations initiatives. They are asking the question “what should be a lab in a the 21st century”, and the further question of who will have access.
THOMAS LANDRAIN Overview of La Pallais in Paris, an open wet lab that started as a squat. Great story of how they created an DNA extraction and analysis project to outpace the available meat analysis product on the market (propelled by a public interest in testing horse vs. cow in commercial meat products in France). Compiled their lab from donated materials from other labs, and moved into the center of Paris to begin testing the model more actively.
MARIA ANGELES SERRANO This talk has totally captivated my imagination, and I’ve been dreaming of the consequences of Seranno’s work ever since. Her work looks for true cartographic maps by assessing the distance in underlying euclidean spherical space. The shorthand way of grasping her work is to consider the shape of an ocean floor by comparing the “2D” surface image (if you are looking straight down in clear static water) and the actual “3D” topography. How these relate has relevance not only to physical topography, but how we analyze the “topography” of networks. Her work identifies the emergence of hyperbolic geometry in networks.