"The modeling of complex systems such as ecological or socio-economic systems can be very challenging. Although various modeling approaches exist, they are generally not compatible and mutually consistent, and empirical data often do not allow one to decide what model is the right one, the best one, or most appropriate one. Moreover, as the recent financial and economic crisis shows, relying on a single, idealized model can be very costly. This contribution tries to shed new light on problems that arise when complex systems are modeled. While the arguments can be transferred to many different systems, the related scientific challenges are illustrated for social, economic, and traffic systems. The contribution discusses issues that are sometimes overlooked and tries to overcome some frequent misunderstandings and controversies of the past.…"

Frankly, I've alway thought this, especially after some early "confusing" experiments that never got published because they were part of my first Ph.D. thesis research: "…We argue that the presence of only the frozen phase in the work of Kauffman et al. was due simply to the specific parametrization used, and is not an inherent feature of this class of functions. However, these networks are significantly more stable than the variants where all possible Boolean functions are allowed."

"Therefore, the underlying demand curve is different today - so it isn't logical to expect valuation metrics of the market to be reproduced today - sans very extreme market events, which would need to last a considerable period of time."

will I ever understand all the effort statisticians put into what I consider a solved problem? Pareto-GP is apparently utterly unknown, still

"Connections in complex networks are inherently fluctuating over time and exhibit more dimensionality than analysis based on standard static graph measures can capture. Here, we introduce the concepts of temporal paths and distance in time-varying graphs. We define as temporal small world a time-varying graph in which the links are highly clustered in time, yet the nodes are at small average temporal distances. We explore the small-world behavior in synthetic time-varying networks of mobile agents, and in real social and biological time-varying systems."

"Small world networks interpolate between fully regular and fully random topologies and simultaneously exhibit large local clustering as well as short average path length. Small world topology has therefore been suggested to support network synchronization. Here we study the asymptotic speed of synchronization of coupled oscillators in dependence on the degree of randomness of their interaction topology in generalized Watts-Strogatz ensembles. We find that networks with fixed in-degree synchronize faster the more random they are, with small worlds just appearing as an intermediate case. For any generic network ensemble, if synchronization speed is at all extremal at intermediate randomness, it is slowest in the small world regime. This phenomenon occurs for various types of oscillators, intrinsic dynamics and coupling schemes."

'It turns out that people’s stated preferences have a weak relationship to who they actually like. Stated preferences, one study found, “seemed to vanish when it came time to choose a partner in physical space.”'

"Computational complexity has in the past adapted well to new computation models from the PRAM to biological and quantum computers. But we are seeing new computing paradigms in multicore and cloud computing and theory seems late to the party. There was a nice SODA paper on MapReduce, the basic cloud computing operation, but for the most part theorists haven't tackled the cloud computing model and only a few have looked at multicore. Theory can say much about new computational methods, both in how we can take advantage of them and what they can't do, but only if we make the effort to develop the proper models to capture these new approaches."

"Presumably, this isn’t the book the libertarians have read, so I assume there must exist another of the same title."

"Personally, if I believed in Republican/Austrian School/Libertarian, I'd either be putting a heck of a lot of time and effort into explaining why the results don't apply, or, if I could not come up with a home run explanation, I'd give up my views.…The fact that members of these dogmas don't know or care that reality doesn't fit their beliefs makes me a bit leery of other things they believe in as well. And yet, Republican/Austrian School/Libertarian is now the dominant paradigm. Even most Democrats believe cutting taxes, for instance increases growth - they just feel that even so, in most cases, the non-growth related benefits of keeping taxes higher (say, to pay for certain programs) makes it worth not cutting taxes in many instances."

"For example, the manual for the Franklin Ace 100 begins with about 40 pages of computer basics (What are they? What can they do? etc). And then, on page 40, two thirds of the way down the page, there is a chapter heading called “The Ancestral Territorial Imperatives of the Trumpeter Swan.” Here’s how the chapter begins:…"

Find myself wondering if one could develop an algorithm to "invent" a taxon that would maximally disrupt the resulting tree structure if added…

"The recent happiness literature suggests that interpersonal utility comparisons are to some extent possible. Yet this does not undermine the basic philosophical criticism of utilitarianism (or, more generally, of subjective welfarism). A focus on subjective utility may lead to a relative neglect of the real conditions of life. Moreover, valuing a life is a reáective activity that should not be reduced to the evaluation of hedonic states. In fact, the psychological literature has also argued that ìutilityîis a multidimensional phenomenon and that it is crucial to distinguish a§ects and cognition. Therefore it appears unlikely that we should witness a revival of primitive utilitarianism in the near future. At the same time, however, the empirical work on happiness has drawn attention to the importance of the non-material dimensions of life ó a welcome shift away from the exclusive focus on material consumption."

"We are pleased to announce the establishment of the new Computational Social Science Society (called CSSS, or “C-triple-S”), officially registered in Washington DC on 16 December, 2009, as a 501 (c)(3) scientific non-profit professional organization to serve members in our field of computational social science. This new organization originated at the last meeting of NAACSOS, when the gathered members unanimously moved to establish the new CSSS and elect officers to provide for continuity of leadership and build on NAACSOS’ best past accomplishments."

"The real problem with the DIKW pyramid is that it's a pyramid. The image that knowledge (much less wisdom) results from applying finer-grained filters at each level, paints the wrong picture. That view is natural to the Information Age which has been all about filtering noise, reducing the flow to what is clean, clear and manageable. Knowledge is more creative, messier, harder won, and far more discontinuous. "

"These are basic life skills that everyone should want to master. If we taught them broadly, and if everyone learned them, then this sort of mastery wouldn’t attract the geek label. But we don’t teach these skills broadly, most people don’t learn them, and the language we use isn’t our friend. If systems thinking is geeky then only geeks will be systems thinkers. We can’t afford for that to be true. We need everyone to be a systems thinker."

"Related, it reminded me a lot of Dan Pink’s thesis from Drive, and his TED talk, of the operators of the “new workforce”, are based in the intrinsic motivation associated with autonomy, mastery, and purpose. Seeing as how I spend far more time looking at the trends of business than of play, I realized…for me (and many others), work is a type of play.

From Nicole’s Four Keys of FUN, I’m proposing the Four Keys to Business.…"

"That someone with such a understanding of complex financial institutions highlights her naiveté, as if things are what they are, not because they are an equilibrium of borrower and saver preferences, but rather, the whims of The Captains of Industry in their top hats. To give her power, would merely reinforce what everyone in the industry knows, that Washington regulators are out-of-touch. For her, competition is simply a "race to the bottom to develop new ways to trick customers", and so we should expect her to create a 'stable' industry, like in our education and postal industries, where there is limited competition but lots of guarantees, and little or no productivity growth."

"Perhaps by coincidence, three new papers in this week’s issue of the NEP-DGE report deal with forecasting. Kolasa, Rubaszek and Skrzypczyński says that DSGE models perform remarkably well. Bache, Jore, Mitchell and Vahey claim that VAR models with structural breaks do better, but of course structural breaks cannot be predicted with a VAR. Gupta, Kabundi and Miller show that DSGE models of real estate markets are better with turning points, which are the most difficult statistic to forecast."

"We can add the inadequate funding of unemployment compensation programs to the ever growing list of things that the crisis has revealed need to be fixed."

"I guess that's what's kind of disappointing to me about Fama's post. I'm thrilled that he's read my book, and is saying halfway nice things about it in public. In general, I'm a big Fama fan—his willingness to keep testing his theories against the evidence, and to support the work of students and younger professors whose research undermined those theories, is hugely admirable. But he and a lot of other people in academic finance just don't seem interested in directly engaging in many of the most interesting questions raised by the financial crisis. Such as: Can the financial sector get too big, and if so how can we tell? Can derivatives markets concentrate risk as well as spread it? Is financial innovation fundamentally different and more dangerous than innovation in other fields, and if so what should we do about it? Should central banks and financial regulators try to snuff out asset-price bubbles, and if so how should they go about determining when we're in bubble territory?…"

"Efficient-market theory ought, with any methodological justice, to be relegated to the Museum of Nice Tries. But there is no unified replacement theory, and developing one will be arduous, involving empirical and theoretical work on all scales, from the experimental psychology of individual investors, through the institutional constraints under which money managers work, to solving for the aggregated effects of market participants’ interactions. In the meantime, efficient-market theory provides a ready basis for precise calculations, and one that is moreover now built into the academic field of finance and into the practice and even infrastructure of the markets."

"It is no wonder that both the political and economic right look back at the McKinley Era for their ideal. No income tax, no universal suffrage in England, no popular election of Senators in the U.S., no insider trading rules, no restrictions on wage suppression. Now that is freedom!!

Prof. Thoma told me a few years ago that "Economics does not handle equity well". And after giving that some long thought I figured out why. Because classical economics does not handle popular democracy well. That is for some people in England everything was downhill after the Reform Act of 1832 with ultimate disaster delivered with Representation of the People Act of 1918, while in the U.S. it was the changes introduced with the 16th, 17th and 19th Amendments.

Damn democracy! Always screwing with this nicely designed business plan!"